title: Caffeic acid production enhancement by engineering a phenylalanine over-producing Escherichia coli strain.
abstract: Caffeic acid is a plant-specific phenylpropanoic acid with multiple health-improving effects reported, and its therapeutic derivatives have also been studied throughout the last decade. To meet its market need and achieve high-level production, microbial production of caffeic acid approaches have been developed in metabolically engineered Escherichia coli. In our previous work, we have established the first artificial pathway that realized de novo production of caffeic acid using E. coli endogenous 4-hydroxyphenylacetate 3-hydroxylase (4HP3H). In this work, we exploited the catalytic potential of 4HPA3H in the whole-cell bioconversion study and produced 3.82 g/L (461.12 mg/L/OD) caffeic acid from p-coumaric acid, a direct precursor. We further engineered a phenylalanine over-producer into a tyrosine over-producer and then introduced the artificial pathway. After adjusting the expression strategy and optimizing the inoculants timing, de novo production of caffeic acid reached 766.68 mg/L. Both results from the direct precursor and simple carbon sources represent the highest titers of caffeic acid from microbial production so far.
authors.affiliation: College of Engineering, University of Georgia, Athens, Georgia.
authors.forename: Qin
authors.initials: Q
authors.lastname: Huang
authors.forename: Yuheng
authors.initials: Y
authors.lastname: Lin
authors.forename: Yajun
authors.initials: Y
authors.lastname: Yan
mesh_terms: D002109:Caffeic Acids / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism*; D060847:Metabolic Engineering / Q000379:methods*; D006899:Mixed Function Oxygenases / Q000235:genetics / Q000378:metabolism; D010649:Phenylalanine / Q000378:metabolism*; D014443:Tyrosine / Q000378:metabolism
chemical_list: D002109:Caffeic Acids; D014443:Tyrosine; D010649:Phenylalanine; D006899:Mixed Function Oxygenases; C026252:4-hydroxyphenylacetate 3-monooxygenase; C040048:caffeic acid
keywords: biosynthesis; caffeic acid; natural products; p-coumaric acid; phenylalanine; tyrosine